Calender stack



United States Patent Inventors Edgar ,I. Justus Beloit, Wisconsin; Carl B. Dahl, Rockton, Illinois Appl. No. 774,469 Filed Nov. 8, 1968 Continuation-in-part of Ser. No. 764,372, filed Sept. 21, 1968, which is a continuation of Ser. No. 572,423, tiled Aug. 15, 1966. Patented Aug. 25, 1970 Assignee Beloit Corporation Beloit, Wisconsin a corporation of Wisconsin CALENDER STACK 17 Claims, 4 Drawing Figs.

U.S.Cl 100/161, 100/170,29/116 Int. Cl B30b 3/04 Field of Search 100/ 1 55,

Primary Examiner-Edward L. Roberts AnameyHill, Sherman, Meroni, Gross and Simpson ABSTRACT: Calender stack including a plurality of stacked calender rolls having nip pressure cooperation with each other and with a bottom king roll. Means are provided for externally relieving the bearing loads on all of the rolls. Means are also provided for externally loading the bearings of alternate rolls and thereby increasing the nip pressures. The rolls in which the bearing loads may be both relieved and loaded are controlled crown rolls having opposed pressure shoes reacting against the stationary center shafts of the rolls, and the inner peripheries of the rolls. The top pressure shoes serve to relieve the nip pressures by trueing the surfaces of the calender rolls while the bottom pressure shoes serve to load the nips between the calender rolls and to equalize the pressure reactions on the center shaft, and to thereby damp vibration of the rolls.

Patented Aug. 25, 1970 Sheet Q NM.- wwwnm M ww- Patented Aug. 25, 1970 3,525,301

Sheet 8 of 3 1M1; W Rs Edgard (/6/8/6/6' C'a fl/ 5 50h/ WM I CALENDERSTACK SUMMARY OF THE INVENTION AND OBJECTS This application is a continuation-in-part of application Ser. No. 764,372, filed Sept. 21, 1968, and entitled Self Damped Calender Roll," which application is a continuation of application Ser. No. 572,423, filed Aug. 15, I966 and now abandoned.

In carrying out the present invention we improve upon the calendering of paper, by providing a calender stack in which alternate rolls are controlled crown rolls having pressure nip cooperation with plain rolls, and in which the bearing loads on the controlled crown rolls may be relieved or loaded and the bearing loads on the plain rolls may be relieved. The controlled crown rolls further have opposed pressure shoes cooperating with the means for loading and relieving the bearing loads on the controlled crown rolls, to provide a wide range of nip pressures with a resultant calender stack capable of attaining a wide range of thicknesses and finishes of papers.

A principal object of the present invention, therefore, is to provide an improved calender stack of a novel construction capable of efficiently controlling the caliper of the paper and thereby attaining a wide variety of paper thicknesses and finishes.

Another object of the invention is to improve upon the calenders for calendering paper heretofore in use by providing means for selectively loading the bearings of certain rolls in the calender stack and providing means for externally loading and relieving the bearing loads of the intermediate rolls in the stack, to provide a wide range of nip pressures.

Another object of the invention is to provide an improved calender stack in which alternate rolls in the stack are controlled crown rolls having force transferring means acting in opposite directions against the shafts for the rolls, and so arranged that the force transferring means can be pressurized individually or uniformly to provide a better control of the nip pressures between the rolls and to damp vibration of the rolls in the stack.

Another object of the invention is to improve upon the calender stacks heretofore in use by using alternate plain and controlled crown rolls in the stack, and by providing the controlled crown rolls with oppositely acting pressure shoes to balance the forces thereon, and reduce vibration of the rolls.

A further object of the invention is to improve upon the calender stacks heretofore in use by alternating the calendering rolls in the stack between plain and controlled crown rolls and providing means selectively operable to relieve the bear ing loads on the plain rolls and providing other means selectively operable to relieve and load the bearings on the controlled crown rolls, in which the controlled crown rolls have oppositely acting force transferring means, controlling the crowns of the rolls and the loading of the pressure nips between the rolls in cooperation with the bearing load relieving and loading means.

These and other objects of the invention will appear from time to time as the following specification proceeds and with reference to the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic view in side elevation ofa calender stack constructed in accordance with the principles of the present invention;

FIG. 2 is a diagrammatic view of a portion of the calender stack shown in FIG. 1 illustrating the fluid pressure connections to provide the required nip pressures between the calender rolls and to equalize the loads on the center shafts of the controlled crown rolls;

FIG. 3 is a sectional view taken along one of the controlled crown rolls shown in FIGS. 1 and 2 and illustrating certain details of the pressure shoes thereof; and

FIG. 4 is a transverse sectional view taken through the roll shown in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment of the invention illustrated in the drawings, we have diagrammatically shown in FIGS. 1 and 2, a calender stack A including a bottom or king roll 10 which may be driven by power in a conventional manner, and a plurality of alternate controlled crown rolls l1 and plain rolls l2 stacked on the bottom roll and forming a pressure nip with the bottom roll and also effective to form individual pressure nips between each pair of alternately arranged rolls 11 and 12.

The calender stack generally includes a pair of parallel spaced upright posts 13, suitably connected in parallel spaced relation with respect to each other and extending upwardly of a base 15, extending forwardly from said posts and having bearing supports l6, 16 extending upwardly of the forwardly projecting portions of the base 15 and forming bearing mountings for the bottom roll 10, in a conventional manner. The bottom roll 10 serves as a finishing roll and is the driven roll of the calender stack although selected intermediate rolls 11 may also be driven rolls. The bottom roll 10 may be driven from a suitable source of power in a conventional manner (not shown) and may have a plated surface, plated with chrome or nickel, to provide a highly polished surface, where the stack is used for glossing treatment. The bottom roll 10 may also be a controlled crown roll, having a pressure shoe 17 extending for the operative length thereof for controlling the crown of the roll where required to provide a true calendering surface.

The superposed rolls 11 and 12 are driven by contact with a web W trained through the nips thereof, and the nip between the roll 11 and the bottom roll 10.

The controlled crown rolls 1], 11 are of a similar structure and each is mounted at its opposite ends on the posts 13, 13 in a similar manner, so the mounting and construction of one roll only need herein be shown and described in detail, and the same part numbers will be applied to the mounting means for each of the rolls.

Each roll 11 is symmetrical on opposite sides of its transverse center, except where the roll may be a driven roll and is shown as including an elongated hollow roll shell 19. The roll shell 19 has an interior cylindrical wall 20, spaced radially outwardly of an inner stationary core or center shaft 21, extending along the interior of the roll shell and beyond opposite ends thereof. The core or center shaft 21 is supported adjacent its opposite ends on bearing support rings 23, mounted in bearing support housings 24, on the outer or forward ends of lift arms 25, in a conventional manner. The lift arms 25 extend rearwardly of the bearing support housings 24 along the inner sides of the posts 13 between bracket members 26, extending forwardly of said posts, and are transversely pivoted to said bracket members on pivot pins 27, mounted in said bracket members at their ends. The arms 25 have top and bottom bearing faces 28 and 29 extending along their rear end portions and disposed rearwardly of said posts.

The top bearing face 28 of each arm 25 serves as a load relieving face and is engaged by a fluid pressure diaphragm 31, disposed between said face and a bracket 32, extending rearwardly of the rear face of the post 13. The fluid pressure diaphragm 31 may be a conventional loading diaphragm commonly used in paper making machines and may be of a type known to the trade as an air spring, and is supplied with fluid under pressure through a fluid pressure line 33, to raise the bearing support housing 24 about the axis of the pivot 27 and relieve the nip load between the roll 11 and its next adjacent downwardly spaced roll 12.

The bottom bearing face 29 is engaged by a diaphragm 35, like the diaphragm 31, and mounted on a bracket 36 extending rearwardly of the post 37. The diaphragm 35 may also be a conventional form of air spring and is supplied with fluid under pressure, such as air, through a fluid pressure line 37 to apply a force to the bottom bearing surface 29 and pivot the bearing support housing 24 about the axis of the pivot shaft 27 and thereby load the bearings for the roll 11 and provide an external loading force on the nip between a roll 11 and its as sociated roll 12. It should be understood that the bearing support housing 24, the lift arms and diaphragms 31 and are mounted on each post 13, to uniformly raise or relieve the bearing loads of the controlled crown rolls l1, and that each controlled crown roll and its mounting is the same, and that all of the rolls 11, 11 may be raised or lowered about the axes of the respective pivot pins 27.

Each core or center shaft 21 is a non-rotatable shaft, and as shown in FIG. 3, supports the roll shell 19 adjacent opposite ends of the shell, on anti-friction bearings 39, which are of a conventional self-aligning type, commonly used to form bearing supports for controlled crown rolls. The opposite ends of the core or center shaft 21 are supported in the bearing support housings 24 in the bearing support rings 23 stationarily mounted in the bearing support housings 24. The support rings 23 each carry an inner ring 41 having a generally spherical inner face 42 and engaging a generally spherical face 43 of a ring 45, mounted on the core or center shaft 21, and retained thereto as by snap rings 46. The bearing support rings 23 thus support the stationary core shaft 21 for bending movement about its opposite ends to take the bending reactions placed thereon. The interior cylindrical wall 20 of the associated roll shell 19 may be loaded by oppositely acting fluid pressure operated shoes 47 and 48, engaging the inner peripheral surface 20 of the roll shell 19, along diametrically opposed regions and reacting against the center shaft 21.

As shown in FIG. 4, the center shaft or core 21 has two diametrically opposed outwardly opening rectangular chan-' nels or grooves 49 and 50 extending therealong and forming pressure chambers for rectangular pistons 51 and 52 respectively, suitably sealed to said channels. The respective pistons 51 and 52 have rock pins 53 and 54 seated therein which form rockable mountings for the respective pressure shoes 47 and 48, as shown and described in application Ser. No. 572,423, filed by Edgar .l. Justus and Carl B. Dahl on Aug. l5, 1966 and entitled Self Damped Calender Roll". The channels 49 and 50 are closed at their opposite ends by closure members 55 and 56 respectively, suitably secured to the ends of said channels and sealed thereto.

Individual fluid pressure passageways 59 and 60 lead into and axially along the center shaft 21 and have communication with radial passageways 61 and 62 respectively opening into the respective channels 49 and 50. The passageways 59 and 60 are respectively connected with fluid pressure lines 63 and 65, and supply fluid under pressure to the channels 49 and 50 under the selective control of valve means (not shown) which may be selectively operable to engage the shoes 47 and 48 with the interior wall 20 of the roll shell 19. The top and bottom pressure shoes 47 and 48 may be independently or simultaneously loaded to control the crown of the associated controlled crown roll 11 and to equalize pressure on opposite sides of the center shaft 21, where required.

It should here be understood that the top shoe 47 may serve to align or straighten the peripheral working surface of the roll shell 19, and acts as a load relieving shoe and that the bottom shoe 48 reacts against the center shaft 21 in a direction opposite to the top shoe and loads the nips between the two rolls 11 and 12 and may equalize pressure on the center shaft 21 and thereby damp vibration of the roll.

A fluid pressure line 64 serves to pressurize the pressure shoe 17 under the selective control of suitable valve means to control the crown of the roll 10, where required. The pressure shoe 17 is constructed and operated like the pressure shoes 47, so a detailed description thereof need not herein be shown or described.

The intermediate plain rolls 12, 12 may be solid rolls and are of a similar construction and are mounted for free rotation at their opposite ends in advance of the posts 13,13 in a manner, which is conventional with paper calenders. The mountings for said rolls, therefore, need not herein be shown or described in detail, and the mountings for one end of one roll need. only be generally described. It will be understood that each roll 12 has a substantial length-to-diameter ratio, such that it responds to load unbalance thereon, e.g., by the full weight of the bearings, by a certain amount of deflection, in a manner recognized by the skilled workers in this art.

Each roll 12 is journalled at its opposite ends in anti-friction bearings (not shown) mounted in bearing housings 66, 66, mounted on the outer ends of lift arms 67, 67 in a conventional manner. Each lift arm 67 extends rearwardly of the bearing housing 66 along the inner side of the respective post 13 between bearing brackets 69, 69 secured to the front face of said post 13 and projecting forwardly therefrom. A pivot pin 70 serves to pivot said lift arm between said brackets.

Each lift arm 67 extends rearwardly along the inner side of its associated post 13 to a position adjacent the rear end thereof and has an upwardly facing bearing surface 71, engaged by the inner end of an actuator arm 72. The actuator arm 72 is pivoted between the furcations of a bifurcated bracket member 73 on a transverse pivot pin 74. A diaphragm 75, such as an air spring, is mounted on its lower end on a projecting portion 76 of the bracket member 73, extending rearwardly of said bracket member beneath the furcations thereof. The opposite side of the diaphragm 75 is seated on a pressure pad 77 on the underside of the actuator arm 72 for pivoting said actuator arm about the axis of the pivot pin 74 on the admission of air to said diaphragm. The diaphragm 75, therefore, serves to move the associated calender roll 12 in an upward direction, to relieve the loads from the bearings of said calender roll and to raise said calender roll, to thread a web therethrough.

Pressure lines 79 leading from a main pressure line 80 supply fluid under pressure to the diaphragms 75 to relieve the loads from the bearings of the calender rolls 12. The pressure line 80 also supplies fluid under pressure to the pressure lines 33 to enable all of the calender rolls to be raised out of engagement with each other, for rethreading the calender (FIG. 2).

The loading diaphragms 35 for externally loading the controlled crown rolls 11 are supplied with fluid under pressure, such as air, through the pressure lines 37, connected with a common pressure line 81 connected with a suitable supply of air under pressure through suitable valve means (not shown) which are no part of the present invention, so need not be shown or described herein.

Thus, air under pressure may be supplied to the diaphragms 31 and 75 for the alternately arranged controlled crown rolls 11 and plain rolls 12 to relieve the loads on the bearings for said rolls when the top pressure shoes 48 are supplied with fluid under pressure to control the crowns of the controlled crown rolls 1 1.

Pressure may be supplied through the pressure line 81 and pressure lines 37 to the loading diaphragms 35, 35 to load the bearings 39 for the controlled crown rolls and increase the nip pressures between the calender rolls at the selection of the operator of the calender. As for example, the loading diaphragms may be pressurized upon pressurizing the lower shoes 48 against the interior walls 20 of the roll shells 19. When loading the lower pressure shoes 48, the pistons 52 react against the center shafts or cores 21 along the bottom of said center shafts while the loading diaphragms 35 will react against the ends of the center shafts in a direction opposite to the load supplied by the bottom shoes 48 and thereby react against the loads placed on the center shaft by the bottom pistons 52.

The top pressure shoes 47, as previously mentioned, serve primarily to control the crown of the controlled crown rolls 1] and relieve the nip loads by training the surface of the roll along the nip between said roll and its next adjacent upper plain roll 12. The pressure lines 63 may be connected with a suitable source of hydraulic fluid under pressure through individual valves (not shown) which may be selectively operable to pressurize the shoes 47 individually or uniformly. The valves are no part of the present invention and may be of any suitable form, so need not be shown or described herein.

The pressure lines 65, supplying fluid under pressure to load the lower shoes 48 are shown in FIG. 2 as being connected with a common pressure line 83, which in turn may be connected with a suitable source of hydraulic fluid under pressure through suitable valve means (not shown). As shown in FIG. 2, all of the bearing shoes 48 may be simultaneously loaded to provide constant selective pressure nips between the rolls 11 and 12 and between the bottom roll 11 and the king roll 10. lt should be understood, however, that where desirable the bottom shoes 48 may be individually loaded to vary the pressure nips.

The valves controlling the admission of fluid under pressure to pressurize the top shoes 47 may also be connected with the pressure line 83 to equalize the pressure reacting against opposite sides of the center shaft 21, and thereby equalize the pressure acting in diametrically opposed directions on the interior of the roll shell. This equalized pressure on the two pressure shoes 47 and 48 will effect damping of vibration of the rolls and thereby prevent barring or corrugation of the calendered paper.

it should here be understood that when it is desired to load the nips between the rolls 11 and 12, fluid under pressure is admitted through the pressure lines 65 toload the interior of the roll shell by the bottom pressure shoes 48. Fluid under pressure may then be admitted through the pressure lines 63 to supply fluid under pressure to pressurize the pressure shoes 47 and balance the pressure reacting against the center shaft 21, and thereby damp vibration of the rolls.

When it is desired to internally relieve the loads in the nips between the rolls l1 and 12, fluid under pressure is admitted through the pressure lines 63 to load the top shoes 47, while pressure is relieved from the bottom shoes 48 to balance the pressure reacting against the center shaft 21.

It should also be understood that one or a selected number of nips may be used for calendering and that the loading and load relieving diaphragms may be used in cooperation with the pressure shoes 47 and 48 to externally load or relieve the loads from the center shafts.

While we have herein shown and described one form in which the invention may be embodied, it may readily be understood that various variations and modifications in the invention may be attained without departing from the spirit and scope of the novel concepts thereof.

We claim:

1. In a calender stack, a plurality of stacked rolls including:

an intermediate roll, and outer rolls having nip pressure cooperation with said intermediate roll;

bearings supporting said rolls;

said outer rolls being plain rolls;

means operable to relieve the bearing loads on all of said rolls;

other means operable to externally load said intermediate roll;

said intermediate roll including:

a roll shell; and

a non-rotatable shaft extending through said roll shell and coaxial therewith; and

first force transferring means between said shaft and said r'oll shell applying a controllable force to the inner surface of said roll shell in an upward direction coextensive with the length of said shell and operable to relieve the nip pressures between said rolls.

2. A calender stack in accordance with claim 1:

wherein second force transferring means is provided for applying a controllable force to the inner surface of said shell in a downward direction. coextensive with the length thereof.

3. A calender stack in accordance with claim 2:

' wherein the first and second force transferring means are fluid pressure operated.

4. A calender stack in accordance with claim 3:

in which the first and second force transferring means are independently operated.

5. A calender stack in accordance with claim 2:

in which the first and second force transferring means are pressure shoes reacting on opposite sides of said shaft for said shell;

in which fluid pressure cylinder and piston means are provided to pressurize said shoes and equalize the forces on opposite sides of said shaft and thereby damp vibration thereof; and

in which independent pressure lines supply pressure to said cylinders on opposite sides of said shaft.

6. A calender stack in accordance with claim 2:

wherein a plurality of intermediate rolls and outer rolls are provided;

wherein said outer rolls have pressure nip cooperation with said intermediate rolls on opposite sides of said nonrotatable shafts for said intermediate rolls; and

wherein the first and second fluid pressure force transferring means comprise pressure shoes coextensive with the length of said roll shell and providing force transferring cooperation between said non-rotatable shafts and said interior cylindrical walls of said roll shells in the region of the pressure nips between said outer rolls and said intermediate rolls.

7. A calender stack in accordance with claim 1:

in which the force transferring means is fluid pressure operated.

8. A calender stack, comprising:

a bottom roll;

a plurality of stacked rolls defining pressure nips therebetween and a pressure nip with said bottom roll, said stacked rolls including a series of intermediate rolls and outer rolls having pressure nip cooperation with said intermediate rolls on opposite sides of said intermediate rolls and having a pressure nip with said bottom roll;

said intermediate rolls each including a hollow roll shell having an interior cylindrical wall, a non-rotatable shaft within said shell; first and second fluid pressure force transferring means on opposite sides of said shaft, coextensive with the length of said roll shell and providing force transferring cooperation between said shaft and said hollow interior cylindrical wall of said roll shell in the region of the pressure nips between said rolls, and operable to relieve or increase the nip pressures and to equalize the forces acting on said center shaft and thereby damp vibration of said calender stack.

9. A calender stack in accordance with claim 8:

wherein the outer rolls are plain rolls; and

wherein means are provided for relieving the bearing loads on all of said rolls.

10. A calender stack in accordance with claim 9:

wherein individual pressure lines are provided to pressurize said pressure shoes acting in an upward direction; and

wherein a common pressure line is provided for pressurizing said shoes acting in a downward direction.

11. A calender stack in accordance with claim 8:

wherein means reacting against opposite ends of said shafts are provided to externally load said intermediate rolls.

12. The calender stack of claim 11:

wherein the means loading said shafts comprise:

rockable support arms therefor; and fluid pressure operated loading diaphragms acting against said arms and moving said shafts in directions toward said bottom roll.

13. The calender stack of claim 12:

wherein load relieving fluid pressure operated diaphragms operate against said arms on the opposite sides thereof from said first mentioned diaphragms, and are selectively operable to relieve the loads on said shafts and to raise the rolls out of engagement with each other for threading.

14. The calender stack of claim 13:

wherein the bottom roll has a crown controlling pressure shoe extending therealong, and has pressure nip cooperation with an intermediate roll; and

16. The calender stack of claim 15:

wherein the bottom roll has a crown controlling pressure shoe extending therealong, and has pressure nip cooperation with an intermediate roll.

17. The calender stack of claim 16: 4

wherein fluid pressure means are provided to pressurize said crown controlling pressure shoe in said bottom roll independently of the pressurizing of said shoes for said intermediate rolls. 

